Abstract

0aThe purpose of this study is to analyze the sensitivity of the RMA2 model parameters reflecting the flow characteristics of stream junction and thus understand the hydraulic characteristics of the channel confluence flow. This study dealt with the input parameters of the RMA-2 model, a two-dimensional numerical analysis model widely used for researches both at home and abroad. The parameters of the RMA-2 model are roughness coefficient, turbulent diffusion coefficient, Coriolis forces latitude, Density, and mesh size. This study those parameters estimated from actual heavy rainfall, and varied the parameter size by (-)30%～h was relatively small, the smaller the approaching angle was, the farther from the junctions became the generating place of the maximum flow velocity, however, when the ratio of the channel width was relatively large, the larger the approaching angle was, the farther the generating place of the maximum flow velocity from the junctions became. In particular, the distance between junctions and the place where the maximum flow velocity generated showed an absolute correlationover 90% of the relative channel width, but an inverse relationwas found when the distance to the place where the flow velocity generated was shortened as relative the channel width between the main channel and tributary increased.

The purpose of this study is to analyze the sensitivity of the RMA2 model parameters reflecting the flow characteristics of stream junction and thus understand the hydraulic characteristics of the channel confluence flow. This study dealt with the input parameters of the RMA-2 model, a two-dimensional numerical analysis model widely used for researches both at home and abroad. The parameters of the RMA-2 model are roughness coefficient, turbulent diffusion coefficient, Coriolis forces latitude, Density, and mesh size. This study those parameters estimated from actual heavy rainfall, and varied the parameter size by (-)30%~+30% to review the characteristics of the flow characteristics of the channel section. Weobserved that when the ratio of the channel width was relatively small, the smaller the approaching angle was, the farther from the junctions became the generating place of the maximum flow velocity, however, when the ratio of the channel width was relatively large, the larger the approaching angle was, the farther the generating place of the maximum flow velocity from the junctions became. In particular, the distance between junctions and the place where the maximum flow velocity generated showed an absolute correlationover 90% of the relative channel width, but an inverse relationwas found when the distance to the place where the flow velocity generated was shortened as relative the channel width between the main channel and tributary increased.

Contents

목차

하도 합류부의 수리학적 특성을 고려한 RMA2 모형 매개변수의 민감도 분석 / 안승섭 ; 임동희 ; 서명준 ; 이효정 1

Abstract 1

1. 서론 1

2. 합류부 흐름 해석 모형의 이론 2

2.1. 기본방정식 2

2.2. 매개변수의 특성 3

3. 수리특성 분석 4

3.1. 연구대상지역의 선정 4

3.2. 매개변수의 추정 4

3.3. 합류부 수리특성인자 5

3.4. 격자망 구성 및 합류부 흐름 해석 5

3.4.1. 조도계수 변화에 따른 흐름해석 5

3.4.2. 난류교환계수 변화에 따른 흐름해석 5

3.4.3. 전향력 변화에 따른 흐름해석 8

3.4.4. 격자크기 변화에 따른 흐름해석 9

4. 결과 및 고찰 10

4.1. 조도계수 변화에 따른 민감도 분석 10

4.2. 난류교환계수 변화에 따른 민감도 분석 10

4.3. 전향력 변화에 따른 민감도 분석 10

4.4. 격자크기 변화에 따른 민감도 분석 10

5. 결론 10

참고문헌 10

References 7

1.

1996，Mid-channel bar growth and its relationship to local flow strength and direction, Earth Surf, Processes Landforms,...